Thymic Indoleamine 2,3-Dioxygenase-Positive Eosinophils in Young Children: Potential Role In Maturation of the Naive Immune System

摘要: Eosinophils expressing indoleamine 2, 3-dioxygenase (IDO) may contribute to T-helper cell (Th)2 predominance. To characterize human thymus IDO+ eosinophil ontogeny relative Th2 regulatory gene expression, we processed surgically obtained thymi from 22 children (age: 7 days 12 years) for immunohistochemistry and molecular analysis, measured cytokine kynurenine levels in tissue homogenates. Luna+ eosinophils (∼2% of total thymic cells) decreased number with age (P = 0.02) were IDO+. Thymic IDO immunoreactivity 0.01) concentration as well. In addition, constitutively-expressed interleukin (IL)-5 IL-13 supernatants was highest youngest children. Eosinophil numbers correlated positively expression the cytokines IL-5, (r 0.44, P 0.002), IL-4 0.46, 0.005), transcription factor signal transducer activator transcription-6 0.68, 0.001), chemokine receptor, CCR3 0.17, 0.04), but negatively IL-17 mRNA −0.57, toll-like receptor 4 −0.74, 0.002). Taken together, these results suggest that functional during infant life have an immunomodulatory role immune responses.